Titanium related phases

Tofl] Tofaute, W., Buettinghaus, A., The Iron rich Comer of the Iron-Titanium-Carbon System (in German), Arch. Eisenhuettenwes., 12(1), 33-37 (1938) (Experimental, Phase Relations, Phase Diagram, 8)... 

Fra] Frage, N.R., Gurevich, Yu.G., Sokolova, A.V., Chumanov, V.I., Stability of Titanium Carbide in Molten Iron and Nickel , Russ. Metall., (3), 30-34 (1989), translated from Izv. Akad. Nauk SSSR, Met, (3), 33-37, (1989) (Phase Relations, Phase Diagram, Thermodyn., Calculations, 8)... 

Art] Artkyukh, L.V., Ilyenko, S.M., Velikanova, T.Ya., The Scandium-Titanium-Carbon Phase Diagram , J. Phase Equilib., 17(5), 403-413 (1996) (Phase Diagram, Phase Relations, Crys. Structure, Experimental, 16)... 

Dew] Dew-Hughes, D., Kaufman, L., Ternary Phase Diagrams of the Manganese-Titanium-Iron and Aluminium-Titanium-Iron Systems a Comparison of Computer Calculations with Experimenf , Calphad, 3, 175-203 (1979) (Thermodyn., Phase Relations, Phase Diagram,... 

Various transition metals have been used in redox processes. For example, tandem sequences of cyclization have been initiated from malonate enolates by electron-transfer-induced oxidation with ferricenium ion Cp2pe+ (51) followed by cyclization and either radical or cationic termination (Scheme 41). ° Titanium, in the form of Cp2TiPh, has been used to initiate reductive radical cyclizations to give y- and 5-cyano esters in a 5- or 6-exo manner, respectively (Scheme 42). The Ti(III) reagent coordinates both to the C=0 and CN groups and cyclization proceeds irreversibly without formation of iminyl radical intermediates.The oxidation of benzylic and allylic alcohols in a two-phase system in the presence of r-butyl hydroperoxide, a copper catalyst, and a phase-transfer catalyst has been examined. The reactions were shown to proceed via a heterolytic mechanism however, the oxidations of related active methylene compounds (without the alcohol functionality) were determined to be free-radical processes. 

It is a mass transfer between a mobile, solid, or liquid phase, and the adsorption bed packed in a reactor. To carry out adsorption, a reactor, where a dynamic adsorption process will occur, is packed with an adsorbent [2], The adsorbents normally used for these applications are active carbons, zeolites and related materials, silica, mesoporous molecular sieves, alumina, titanium dioxide, magnesium oxide, clays, and pillared clays. 

Photo-initiated AOPs are subdivided into VUV and UV oxidation that are operated in a homogeneous phase, and in photocatalysis (Fig. 5-15). The latter can be conducted in a homogeneous aqueous phase (photo-enhanced Fenton reaction) or in a heterogeneous aqueous or gaseous phase (titanium dioxide and certain other metal oxide catalysts). These techniques apply UV-A lamps or solar UV/VIS radiation and they are in pre-pilot or pilot status. According to Mukhetjee and Ray (1999) the development of a viable and practical reactor system for water treatment with heterogeneous photocatalysis on industrial scales has not yet been successfully achieved. This is mainly related to difficulties with the efficient distribution of electromagnetic radiation (UV/VIS) to the phase of the nominal catalyst. 

The catalytic oxidation of hydrocarbons with peroxides, especially the epoxidation of olefins, in liquid phase by titanium catalysts is one of the most actively investigated reactions (60). The active species for this epoxidation reaction is usually assumed to be titanium peroxo moieties, derived from four-coordinate titanium and peroxides. However, the isolation of the active intermediate remains a challenge owing to the inherent instability of such species. We have been able to synthesize and stabilize the related cubic p-oxo-silicon-titanium complex (35) by reacting a bulky... 

This cubic silicon-titanium g-oxo complex was also shown to be a model system for insoluble titanosilicates and related catalysts which have been used for epoxidation reactions of olefins. The cubic silicon-titanium g-oxo complex, when immobilized on a silica matrix by dissolving it in tetraethoxysilane and further treatment with acetic anhydride followed by heating up to 60 °C for 20 h, resulted in the formation of a Si02—Ti02 mixed oxide (63). The resulting solid was separated by filtration, and the filtrate formed a gel in about 1 week. This gel showed an enhanced catalytic activity (epoxidation yield of cyclohexene was 72%) as a solid catalysf for epoxidation of cyclohexene in the presence of TBHP in the liquid phase. 

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